Electron microscopic lesions of buccal and gingival tissues will be examined in human diabetes, first degree relatives of diabetics and an animal model, the Chinese hamster. We seek to examine whether such lesions are found in buccal and gingival tissues in humans, whether this procedure can replace needle biopsy as a tool for identifying future diabetics, and for correlation with complications, duration, and control of hyperglycemia in overt diabetes. In the Chinese hamster we will examine basement membrane thickening in the cheek pouch and gingival tissues of diabetic and non-diabetic animals. Furthermore, we will follow the course of basement membrane thickening in animals which undergo hypophysectomy prior to the development of overt diabetes to study whether growth hormone deficiency will prevent the development of diabetic microvascular disease.